Bright nickel electroplating bath and process

Abstract

A primary brightener for use in aqueous nickel electroplating baths has the following general formula: ##STR1## wherein: R 1 is methyl, ethyl or a hydroxyethyl radical; R 2 is alkenyl, alkynyl, hydroxy-substituted alkynyl or lower alkyl-substituted alkynyl; R 3 is lower alkylene, lower alkoxyalkylene, lower alkynylene, lower alkoxy-alkenylene, hydroxy-substituted lower alkylene, carboxy-substituted lower alkylene or hydroxy- and methyl-substituted lower aminoalkylene; R 4 is a sulfonic radical (--SO 3 --) or an aliphatic carboxyester group ##STR2## where R 5 is alkyl, alkenyl, alkynyl, alkoxyalkynyl, dialkoxyalkynyl, hydroxyalkyl, hydroxyalkenyl, hydroxyalkynyl, haloalkyl, halohydroxyalkyl, halohydroxyalkynyl or hydroxyalkoxyalkynyl; and X is halogen or hydroxy when the positive charge on the nitrogen atom is not otherwise neutralized and X is absent when said charge is neutralized by another substituent of the molecule.

I claim: 
     
       1. In a bath for electrodepositing bright nickel and comprising an acidic aqueous solution of nickel ions, the improvement which comprises, dissolved therein, an effective amount of a nickel brightener of formula: ##STR23## wherein: R 1  is selected from the group consisting of methyl, ethyl and hydroxyethyl; R 2  is selected from the group consisting of alkenyl, alkynyl, hydroxy-substituted alkynyl and lower alkyl-substituted alkynyl;   R 3  is selected from the group consisting of lower alkylene, lower alkoxyalkylene, lower alkenylene, lower alkoxyalkenylene, hydroxy-substituted lower alkylene, carboxy-substituted lower alkylene, and hydroxy- and methyl-substituted lower amino-alkylene;   R 4  is selected from the group consisting of a sulfonic radical (--SO 3   - ) and an aliphatic carboxy-ester group ##STR24##  where R 5  is alkyl, alkenyl, alkynyl, alkoxyalkynyl, dialkoxyalkynyl, hydroxyalkyl, hydroxyalkenyl, hydroxyalkynyl, haloalkyl, halohydroxyalkyl, halohydroxyalkynyl or hydroxyalkoxyalkynyl; and   X is selected from the group consisting of halogen and hydroxy when the positive charge on the nitrogen atom is not otherwise neutralized and X is absent when said charge is neutralized by another substituent of the molecule.   
     
     
       2. A bath as defined in claim 1 wherein said brightener is present in a concentration in the range of about 0.01 to 3.0 grams per liter of bath. 
     
     
       3. A bath as defined in claim 1 wherein said brightener is the compound: ##STR25## 
     
     
       4. A bath as defined in claim 1 wherein the said brightener is the compound: ##STR26## 
     
     
       5. A bath as defined in claim 1 which contains additionally, dissolved therein, about 1.0 to 10.0 grams per liter of a secondary brightener selected from the group consisting of o-benzoyl sulfimide, sodium vinyl sulfonate, sodium allylsulfonate, sodium propyne sulfonate, and sodium propynoxy ethane sulfonate. 
     
     
       6. A bath as defined in claim 5 which contains additionally, dissolved therein, about 0.05 to 1.0 grams per liter of an acetylenic alcohol. 
     
     
       7. The bath as defined in claim 6 wherein said alcohol is 2-butyne-1,4-diol; said secondary brightener is O-benzoyl sulfimide; and said brightener is the compound: ##STR27## 
     
     
       8. In a method of electrodepositing nickel on a basis metal from a bath comprising an acidic aqueous solution of nickel ions and an effective amount of a nickel brightener, the improvement which comprises, as said brightener, a compound of formula: ##STR28## wherein: R 1  is selected from the group consisting of methyl, ethyl and hydroxyethyl; R 2  is selected from the group consisting of, alkenyl, alkynyl, hydroxy-substituted alkynyl and lower alkyl-substituted alkynyl;   R 3  is selected from the group consisting of lower alkylene, lower alkoxyalkylene, lower alkenylene, lower alkoxyalkenylene, hydroxy-substituted lower alkylene, carboxy-substituted lower alkylene, and hydroxy- and methyl-substituted lower amino-alkylene;   R 4  is selected from the group consisting of a sulfonic radical (--SO 3   - ) and an aliphatic carboxy-ester group ##STR29##  where R 5  is alkyl, alkenyl, alkynyl, alkoxyalkynyl, dialkoxyalkynyl, hydroxyalkyl, hydroxyalkenyl, hydroxyalkynyl, haloalkyl, halohydroxyalkyl, halohydroxyalkynyl or hydroxyalkoxyalkynyl; and   X is selected from the group consisting of halogen and hydroxy when the positive charge on the nitrogen atom is not otherwise neutralized and X is absent when said charge is neutralized by another substituent of the molecule.   
     
     
       9. The method as defined in claim 8 wherein said brightener is present in a concentration in the range of about 0.01-3.0 grams per liter of bath. 
     
     
       10. The method as defined in claim 8 wherein said brightener is the compound: ##STR30## 
     
     
       11. The method as defined in claim 8 wherein said brightener is the compound: ##STR31## 
     
     
       12. The method as defined in claim 8 wherein said bath contains additionally, dissolved therein, about 1.0 to 10.0 grams per liter of a secondary brightener selected from the group consisting of o-benzoyl sulfimide, sodium vinyl sulfonate, sodium allylsulfonate, sodium propyne sulfonate, and sodium propyroxy ethane sulphonate. 
     
     
       13. The method as defined in claim 12 wherein said bath contains additionally, dissolved therein, about 0.05 to 1.0 grams per liter of an acetylenic alcohol. 
     
     
       14. The method as defined in claim 13 wherein said alcohol is 2-butyne-1,4-diol; said secondary brightener is O-benzoyl sulfimide; and said brightener is the compound: ##STR32##